Display apparatus and electronic device with improved chromaticity

ABSTRACT

Disclosed herein is a display apparatus including: a first pixel including three sub-pixels for displaying three primary colors respectively; and a second pixel including three sub-pixels for displaying two colors selected among the three primary colors and a predetermined color other than the three primary colors, wherein, in the first pixel, the size of the display surface of a sub-pixel for displaying a specific color included in the three primary colors as a specific color missing from the second pixel is larger than each of the sizes of the display surfaces of the two other sub-pixels for displaying the two other primary colors respectively.

BACKGROUND

The present disclosure relates to a display apparatus and electronicequipment.

In recent years, in a display apparatus such as a liquid-crystal displayapparatus, an electro-luminance display apparatus or a plasma displayapparatus, the power consumption for the increasing performance of theapparatus raises a problem. In particular, accompanying the higherresolution, the increased color reconstruction range or the risingluminance in typically the liquid-crystal display apparatus, the powerconsumed by the backlight of the display apparatus inevitably increases.

In order to solve the problem described above, there is proposed atechnology providing a proposed configuration of a color image by addinga sub-pixel for displaying the W (white) color to three sub-pixels fordisplaying the R (red), G (green) and B (blue) primary colorsrespectively. The three sub-pixels for displaying the primary colorsform one pixel used as the unit for formation of the color image. Fordetails, refer to documents such as Japanese Patent No. 3167026.

By adding the sub-pixel for displaying the white color to the threesub-pixels for displaying the primary colors as described above, theluminance can be increased. In addition, if the proposed configurationincluding the four sub-pixels (that is, the RGBW sub-pixels) is allowedto consume the same power as the existing configuration including thethree sub-pixels for displaying the primary colors, the proposedconfiguration will provide luminance higher than that of the existingconfiguration. In other words, in order to let the proposedconfiguration provide luminance equal to that of the existingconfiguration, smaller power consumption is required by the proposedconfiguration.

In the technology disclosed in Japanese Patent No. 3167026, however, theaddition of the W sub-pixel raises the number of signal lines and thenumber of scanning lines by increases corresponding to the addition.Thus, the aperture ratio representing the amount of transmitted lightdecreases. As a result, there is raised a problem that the luminancedoes not increase much in spite of the fact that the W sub-pixel isadded. In addition, since the number of driven lines increases, thefrequency at which a pixel array section is driven also increases. Thus,there is also raised a problem that the power consumption risesundesirably.

In order to solve the problems described above, there is provided atechnology disclosed in documents such as Japanese Patent Laid-open No.2010-33014. In accordance with this technology, typically, the luminanceof the entire image is increased. As a result, it is possible to insertthe W sub-pixel while substantially reducing the power consumption ofthe backlight, displaying the image at a proper luminance and minimizingthe reduction of the aperture ratio.

SUMMARY

In accordance with the existing technology disclosed in Japanese PatentLaid-open No. 2010-33014, as shown in FIG. 10 for example, the pixelarray includes one B sub-pixel and one W sub-pixel at a rate of onesub-pixel per two pixels. That is to say, one of the two pixels includesRGB sub-pixels whereas the other pixel includes RGW sub-pixels. In sucha configuration, the RGBW sub-pixels have the same size which isreferred to as a pixel size.

In the configuration described above, as shown in FIG. 11, in thewhite-color chromaticity displayed as all-pixel lighting (such as 255outputs expressed by 8 bits), there is raised a problem in which atarget chromaticity is shifted to the yellow-color side which is a sideof a supplementary-color system. This problem is referred to as theso-called yellow-color transition which is a shift to the yellow color.In the figure, a typical point at coordinates x=0.31 and y=0.33 in a CIE(Commission International de l'Eclairage) chromaticity diagram is takenas a target chromaticity.

This is because the pixel configuration without a W sub-pixel isdesigned to satisfy the white-color chromaticity target which is shownas a circle in the figure. Then, from this design, one of every two Bsub-pixels is simply replaced with a W sub-pixel so that components ofthe blue color are not adequate. Thus, the so-called yellow-colortransition occurs.

In a light blocking film referred to as a black matrix for blockinglight propagating between sub-pixels or in a light blocking metal on aTFT (Thin Film Transistor) array side, on the other hand, there isadopted means for blocking light propagating through desired sub-pixelssuch as the G sub-pixel or both the R and G sub-pixels. By adoption ofsuch means, it is possible to avoid the yellow-color transition which isa shift of the chromaticity of the yellow color as described above. Inthis case, however, a sub-pixel is simply protected against light sothat there is raised a problem that the transmittance of the displaypanel is reduced substantially.

The above description has explained a problem caused by the yellow-colortransition occurring in a configuration wherein some B sub-pixels of thesub-pixels for the three primary colors (that is, the RGB colors) areeach eliminated and replaced with a W sub-pixel. Instead of replacingsome B sub-pixels with W sub-pixels, however, some R or G sub-pixels canalso be replaced with W sub-pixels. Also in this case, there is raised aproblem that the chromaticity of the white color is shifted to the sideof a supplementary-color system. In addition, this problem is raised notonly in a configuration in which W sub-pixels are added to sub-pixelsfor the three primary colors, but also in a configuration includingadditional sub-pixels for displaying a supplementary-color system suchas a Y (yellow) supplementary-color system or a C (cyan)supplementary-color system.

It is thus an aim of the present disclosure to provide a displayapparatus capable of reducing a shift of the chromaticity of the whitecolor to the side of a supplementary-color system in a process ofconfiguring a pixel by adding a white sub-pixel or a supplementary-colorsub-pixel to sub-pixels for the three primary colors and provideelectronic equipment employing the display apparatus.

In order to achieve the aim described above, the present disclosureprovides a display apparatus including:

a first pixel including three sub-pixels for displaying three primarycolors respectively; and

a second pixel including three sub-pixels for displaying respectivelytwo colors selected among the three primary colors and a predeterminedcolor other than the three primary colors.

The display apparatus is characterized in that, in the first pixel, thesize of the display surface of a sub-pixel for displaying a specificcolor included in the three primary colors as a specific color missingfrom the second pixel is larger than each of the sizes of the displaysurfaces of the two other sub-pixels for displaying the two otherprimary colors respectively.

The display apparatus according to embodiments of the present disclosurecan be employed in various kinds of electronic equipment, which has adisplay section, to serve as the display section of the equipment.

As is obvious from the above description, the second pixel is created bycombining first and second sub-pixels, eliminating a third sub-pixel fordisplaying a specific one of the three primary colors and replacing thethird sub-pixel with an additional sub-pixel for displaying a colordetermined in advance. Thus, the color component of the specific colormissing from the second pixel decreases. As a result, the chromaticityof the white color is shifted to the side of a supplementary-colorsystem.

In the first pixel of the display apparatus, on the other hand, the sizeof the display surface of a sub-pixel for displaying the specific colorincluded in the three primary colors as the specific color missing fromthe second pixel is made larger than each of the sizes of the displaysurfaces of the two other sub-pixels for displaying the two otherprimary colors respectively. Thus, the effective color component of thespecific color missing from the second pixel increases. As a result, itis possible to decrease a shift caused by the specific color missingfrom the second pixel as the shift of the chromaticity of the whitecolor to the side of the supplementary-color system.

In order to achieve the object described above, the present disclosureprovides a display apparatus having pixels each including foursub-pixels for displaying respectively the three primary colors and apredetermined color other than the three primary colors. In this displayapparatus, the size of the sub-pixel for displaying a specific colorselected from the three primary colors is smaller than each of the sizesof the sub-pixels for displaying the two other primary colors but largerthan half the size of each of the sub-pixels for displaying the twoother primary colors. The display apparatus according to the embodimentsof the present disclosure can be employed in various kinds of electronicequipment, which has a display section, to serve as the display sectionof the equipment.

As described above, in each pixel, the size of the sub-pixel fordisplaying a specific color selected from the three primary colors ismade smaller than each of the sizes of the sub-pixels for displaying thetwo other primary colors so that an area can be made available in thepixel due to the smaller size of the sub-pixel for displaying thespecific color selected from the three primary colors. Thus, it ispossible to place the sub-pixel for displaying the predetermined colorin the available area. In addition, since each pixel has the sub-pixelfor displaying the predetermined color, the display performance can beenhanced. For example, the luminance can be increased. On top of that,the size of the sub-pixel for displaying the specific color selectedfrom the three primary colors is made larger than half the size of eachof the sub-pixels for displaying the two other primary colors. Thus, thecomponent of the specific color can be made greater than that of a casein which the size of the sub-pixel for displaying the specific colorselected from the three primary colors is made equal to half the size ofeach of the sub-pixels for displaying the two other primary colors. As aresult, it is possible to decrease the shift of the chromaticity of thewhite color to the side of the supplementary-color system.

The display apparatus according to the embodiment of the presentdisclosure is capable of increasing the effective color component of aspecific color, which is missing from the second pixel, in the firstpixel. Thus, it is possible to decrease a shift caused by the specificcolor missing from the second pixel as the shift of the chromaticity ofthe white color to the side of the supplementary-color system.

In addition, in accordance with the other display apparatus according tothe embodiment of the present disclosure, in each pixel, the size of thesub-pixel for displaying a specific color selected from the threeprimary colors is reduced so that an area can be made available in thepixel due to the smaller size of the sub-pixel for displaying thespecific color. Thus, it is possible to place a sub-pixel for displayinga color determined in advance in the available area. On top of that, thecomponent of the specific color can be increased because the size of thesub-pixel for displaying the specific color is made larger than half thesize of each of the sub-pixels for displaying the two other primarycolors. Accordingly, it is possible to decrease the shift of thechromaticity of the white color to the side of the supplementary-colorsystem.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system configuration diagram showing a rough configurationof a liquid-crystal display apparatus having an active matrix type inaccordance with an embodiment of the present disclosure;

FIG. 2 is a circuit diagram showing basic circuit configurations ofpixels;

FIG. 3 is a diagram showing the top view of a pixel array according to afirst typical implementation of a first embodiment;

FIG. 4 is a table comparing the size of the display surface of a Gsub-pixel with the sizes of the display surfaces of B and W sub-pixels;

FIG. 5 is a diagram showing a chromaticity characteristic of the whitecolor for the first typical implementation;

FIG. 6 is a diagram showing a relation between the aperture ratio andthe panel transmittance (or the luminance) for the first typicalimplementation;

FIG. 7 is a diagram showing the top view of a pixel array according to asecond typical implementation of the first embodiment;

FIG. 8 is a diagram showing the top view of a pixel array according to athird typical implementation of the first embodiment;

FIG. 9 is a diagram showing the top view of a pixel array according to atypical implementation of a second embodiment;

FIG. 10 is a diagram showing the top view of a pixel array including R,G, B and W sub-pixels having the same size; and

FIG. 11 is an xy chromaticity diagram to be referred to in explanationof yellow-color transition of the chromaticity of the white color.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

By referring to the diagrams, the following description explains detailsof embodiments which are each an implementation of the technologyaccording to the present disclosure. However, implementations of thepresent disclosure are by no means limited to the embodiments. Forexample, a variety of numbers used in the embodiments are typical. Inthe following description, the same elements or elements having the samefunctions are denoted by the same reference numeral and such elementsare explained only once. It is to be noted that the followingdescription explains the embodiments in the following order:

1: General Explanation of the Display Apparatus According to anEmbodiment of the Disclosure

2: Liquid-Crystal Display Apparatus According to the Disclosure

2-1: System Configuration

2-2: Pixel Circuit

3: First Embodiment (Pixel Including Three Sub-pixels)

3-1: First Typical Implementation

3-2: Second Typical Implementation

3-3: Third Typical Implementation

4: Second Embodiment (Pixel Including Four Sub-pixels)

4-1: Typical Implementation

5: Liquid-Crystal Display Apparatus of a Horizontal Electric-Field Mode

6: Electronic Equipment

7: Configurations of the Disclosure

1: General Explanation of the Display Apparatus According to anEmbodiment of the Disclosure

The display apparatus according to an embodiment of the presentdisclosure is a display apparatus for showing color displays. The unitfor creating a color image on a pixel array included in the displayapparatus is referred to as a pixel including three or four sub-pixels.That is to say, the pixel array includes a plurality of pixels eachincluding either three or four sub-pixels. The display apparatus forshowing color displays can be a commonly known display apparatus such asa liquid-crystal display apparatus, an electro-luminance displayapparatus or a plasma display apparatus.

The pixel array includes a plurality of pixels which may each includeeither three or four sub-pixels. In either case, the pixels each includethree sub-pixels for displaying three primary colors, that is, the R(red), G (green) and B (blue) primary colors respectively. By turning onall the three sub-pixels at the same time, a white color can bedisplayed. In addition, a combination of sub-pixels to be turned onallows a desired color to be displayed.

In addition to the sub-pixels for displaying the R, G and B primarycolors, a sub-pixel for displaying a predetermined color other than theR, G and B primary colors can be provided in order to enhance thedisplay performance. To put it concretely, by adding a sub-pixel fordisplaying typically the W (white) color as the predetermined color, theluminance can be increased. In addition, by adding a sub-pixel fordisplaying a supplementary-color system such as a Y (yellow)supplementary-color system or a C (cyan) supplementary-color system, thecolor reconstruction range can be widened.

Pixel Including Three Sub-Pixels

In the case of a pixel array including pixels each including threesub-pixels, it is desirable that the pixel array is configured into aconfiguration in which first pixels each including three sub-pixels fordisplaying three primary colors respectively as well as second pixelseach including three sub-pixels for displaying two colors selected amongthe three primary colors and a predetermined color other than the threeprimary colors are laid out alternately in the row and columndirections. In this case, the row direction is defined as a directionparallel to the directions of the pixel rows. That is to say, the rowdirection is a direction in which pixels are laid out on a pixel row. Onthe other hand, the column direction is defined as a direction parallelto the directions of the pixel columns. That is to say, the columndirection is a direction in which pixels are laid out on a pixel column.

In the first pixel, it is desirable to provide a configuration in whichthe size (or the area) of the display surface of a sub-pixel fordisplaying a specific color included in the three primary colors as aspecific color missing from the second pixel is made larger than each ofthe sizes of the display surfaces of the two other sub-pixels fordisplaying the two other primary colors respectively. In this case, theword ‘larger’ means not only ‘strictly larger,’ but also ‘substantiallylarger.’ Existence of a variety of variations generated at the designstage or the manufacturing stage is tolerated.

In addition, the display surface of a sub-pixel is defined as a surfacecontributing to the image display of the sub-pixel. Thus, the size ofthe display surface is determined by the size of the sub-pixel itself.As an alternative, the display surface of a sub-pixel can also be anaperture area which is the size of an aperture created on the displaysurface by a light blocking film referred to as the so-called blackmatrix for blocking light propagating between sub-pixels.

In the second pixel, it is possible to provide a configuration in whichthe size of the display surface of a sub-pixel for displaying thepredetermined color is larger than each of the sizes of the displaysurfaces of the two other sub-pixels for displaying the two otherprimary colors respectively. In this configuration, it is desirable thatthe size of the display surface of a sub-pixel included in the firstpixel to serve as a sub-pixel for displaying a specific color includedin the three primary colors as a specific color missing from the secondpixel is equal to the size of the display surface of a sub-pixelincluded in the second pixel to serve as a sub-pixel for displaying thepredetermined color. With such a configuration, it is possible toprovide a stripe array in which the sub-pixels for displaying thespecific color included in the three primary colors and the sub-pixelsfor displaying the predetermined color are laid out to form a straightline in the column direction.

In the second pixel, it is desirable that the specific color included inthe three primary colors as a specific color missing from the secondpixel is the B (blue) color which has the lowest spectral luminousefficiency among the three primary colors. However, the two primarycolors other than the B (blue) color are not ruled out. As describedbefore, the two primary colors other than the B (blue) color are the R(red) and G (green) colors. In addition, it is desirable that theadditional predetermined color used as a replacement for the specificcolor included in the three primary colors as a specific color missingfrom the second pixel is the W (white) color.

If the specific color included in the three primary colors as a specificcolor missing from the second pixel is the blue color and the additionalpredetermined color used as a replacement for the specific color is thewhite color, in the first pixel, it is desirable to provide aconfiguration in which the size of the display surface of the sub-pixelfor displaying the blue color is made larger than the size of thedisplay surface of the sub-pixel for displaying the green color. In thiscase, the word ‘larger’ means not only ‘strictly larger,’ but also‘substantially larger.’ Existence of a variety of variations generatedat the design stage or the manufacturing stage is tolerated.

In addition, in the second pixel, it is desirable to provide aconfiguration in which the size of the display surface of the sub-pixelfor displaying the white color is made larger than the size of thedisplay surface of the sub-pixel for displaying the green color. In thiscase, in the first and second pixels, it is possible to provide aconfiguration in which the size of the display surface of the sub-pixelfor displaying the red color is made larger than the size of the displaysurface of the sub-pixel for displaying the green color.

As an alternative, in the first and second pixels, it is possible toprovide a configuration in which the size of the display surface of thesub-pixel for displaying the red color is made equal to the size of thedisplay surface of the sub-pixel for displaying the green color. In thiscase, it is desirable to provide a configuration in which the size ofthe display surface of the sub-pixel for displaying the blue color inthe first pixel and the size of the display surface of the sub-pixel fordisplaying the white color in the second pixel are each made larger thanthe sum of the size of the display surface of the sub-pixel fordisplaying the red color and the size of the display surface of thesub-pixel for displaying the green color.

As another alternative, in the first and second pixels, it is possibleto provide a configuration in which the size of the display surface ofthe sub-pixel for displaying the green color is made larger than thesize of the display surface of the sub-pixel for displaying the redcolor.

As is obvious from the above description, the second pixel is created bycombining first and second sub-pixels, eliminating a third sub-pixel fordisplaying a specific one of the three primary colors and replacing thethird sub-pixel with an additional sub-pixel for displaying a colordetermined in advance. Thus, the color component of the specific colormissing from the second pixel decreases. To be more specific, the colorcomponent of the specific color missing from the second pixel decreasesby half. As a result, the chromaticity of the white color is shifted tothe side of a supplementary-color system.

In the case of the display apparatus according to the embodiment of thepresent disclosure, on the other hand, in the first pixel, the size ofthe display surface of a sub-pixel for displaying a specific colorincluded in the three primary colors as a specific color missing fromthe second pixel is made larger than each of the sizes of the displaysurfaces of the two other sub-pixels for displaying the two otherprimary colors respectively. Thus, the effective color component of thespecific color missing from the second pixel increases. As a result, itis possible to decrease a shift caused by the disappearance of thespecific color from the second pixel as the shift of the chromaticity ofthe white color to the side of the supplementary-color system.

In addition, without means adopted in a light blocking film referred toas a black matrix or in a light blocking metal on a TFT array side toserve as means for blocking light propagating through desiredsub-pixels, it is possible to decrease the shift of the chromaticity ofthe white color to the side of the supplementary-color system. Thus, itis possible to improve performance deteriorations caused by theyellow-color transition of the chromaticity of the white color whilesustaining the transmittance of the display panel.

Pixel Including Four Sub-Pixels

In the case of a pixel array including pixels each including foursub-pixels, the four sub-pixels display the three primary colors and apredetermined color other than the three primary colors. In such a pixelarray, it is desirable to provide a configuration in which the pixelsare laid out repeatedly in the row and column directions. As describedabove, the row direction is defined as a direction parallel to thedirections of the pixel rows. That is to say, the row direction is adirection in which pixels are laid out on a pixel row. On the otherhand, the column direction is defined as a direction parallel to thedirections of the pixel columns. That is to say, the column direction isa direction in which pixels are laid out on a pixel column.

In each pixel, it is desirable to provide a configuration in which thesize of the sub-pixel for displaying a specific color selected from thethree primary colors is made smaller than the each of the sizes of thesub-pixels for displaying the two other primary colors but larger thanhalf the size of each of the sub-pixels for displaying the two otherprimary colors. In this case, the word ‘smaller’ means not only‘strictly smaller,’ but also ‘substantially smaller’ whereas the word‘larger’ means not only ‘strictly larger,’ but also ‘substantiallylarger.’ Existence of a variety of variations generated at the designstage or the manufacturing stage is tolerated.

In addition, the size of the display surface of a sub-pixel is definedas the size of the sub-pixel itself and the light blocking film referredto as the black matrix is not included. In other words, since signallines are provided in the column direction between sub-pixels, the sizeof a sub-pixel is determined by the distance between two adjacent signallines.

In each pixel, it is possible to provide a configuration in which thesize of the sub-pixel for displaying a specific color selected from thethree primary colors is made equal to the size of the sub-pixel fordisplaying the predetermined color. In this case, the word ‘equal’ meansnot only ‘strictly equal,’ but also ‘substantially equal.’ Existence ofa variety of variations generated at the design stage or themanufacturing stage is tolerated.

It is desirable that the specific color displayed by the sub-pixelhaving a small size is the B (blue) color which has the lowest spectralluminous efficiency among the three primary colors. However, the twoprimary colors other than the B (blue) color are not ruled out. Asdescribed before, the two primary colors other than the B (blue) colorare the R (red) and G (green) colors. In addition, it is desirable thatthe predetermined color added to the three primary colors is the W(white) color.

If the specific color displayed by the sub-pixel having a small size isthe blue color and the predetermined color is the W white color, it ispossible to provide a configuration in which the size of the sub-pixelfor displaying the blue color is made smaller than each of the sizes ofthe sub-pixels for displaying the red and green primary colors butlarger than half the size of each of the sub-pixels for displaying thered and green primary colors. In this case, it is desirable that thesize of the sub-pixel for displaying the red color is made equal to thesize of the sub-pixel for displaying the green color.

As described above, the size of the sub-pixel for displaying a specificcolor selected from the three primary colors is made smaller than thesizes of the sub-pixels for displaying the two other primary colors sothat the size of the sub-pixel for displaying the specific color becomessmaller. Due to the small size of the sub-pixel for displaying thespecific color, it is possible to provide an available area in which thesub-pixel for displaying the predetermined color is provided. Thus, eachpixel is provided with the sub-pixel for displaying the predeterminedcolor so that the display performance can be enhanced. For example, ifthe white color is taken as the predetermined color, the luminance canbe increased.

In addition, as described above, the size of the sub-pixel fordisplaying the specific color selected from the three primary colors ismade smaller than each of the sizes of the sub-pixels for displaying thetwo other primary colors but larger than half the size of each of thesub-pixels for displaying the two other primary colors. Thus, thecomponent of the specific color can be made larger than that of aconfiguration in which the size of the sub-pixel for displaying thespecific color is made equal to half the size of each of the sub-pixelsfor displaying the two other primary colors. As a result, it is possibleto decrease the shift of the chromaticity of the white color to the sideof the supplementary-color system.

On top of that, since each pixel includes sub-pixels for displaying allthe three primary colors, the resolution can be enhanced.

In addition, without means adopted in a light blocking film referred toas a black matrix or in a light blocking metal on a TFT array side toserve as means for blocking light propagating through desiredsub-pixels, it is possible to decrease the shift of the chromaticity ofthe white color to the side of the supplementary-color system. Thus, itis possible to improve performance deteriorations caused by theyellow-color transition of the chromaticity of the white color whilesustaining the transmittance of the display panel.

2: Liquid-Crystal Display Apparatus According to the Disclosure

2-1: System Configuration

FIG. 1 is a system configuration diagram showing a rough configurationof a display apparatus 10 according to the embodiment of the presentdisclosure. A typical example of the display apparatus according to theembodiment of the present disclosure is a liquid-crystal displayapparatus having an active matrix type. In the following description, aliquid-crystal display apparatus is taken as a typical example of thedisplay apparatus according to the embodiment of the present disclosure.However, examples of the display apparatus according to the embodimentof the present disclosure are by no means limited to a liquid-crystaldisplay apparatus. That is to say, the display apparatus according tothe embodiment of the present disclosure can be any commonly knowndisplay apparatus such as an electro-luminance display apparatus or aplasma display apparatus.

The liquid-crystal display apparatus has a panel structure including twosubstrates not shown in the figure. At least, one of the substrates is atransparent one. The two substrates face each other and are separatedfrom each other by a gap determined in advance. Liquid crystals areenclosed in the gap between the two substrates. The operating mode ofthe liquid-crystal display apparatus also referred to as aliquid-crystal display panel is not prescribed in particular. Forexample, the liquid-crystal display apparatus can be configured to bedriven in the so-called TN mode, a VA mode or an IPS mode.

As shown in FIG. 1, the liquid-crystal display apparatus 10 according toa typical implementation of an embodiment includes a pixel array section30 and a driving section provided at locations surrounding the pixelarray section 30. The pixel array section 30 has a plurality of pixels20 each including a liquid-crystal capacitor. The pixels 20 are laid outtwo-dimensionally to form a pixel matrix on the pixel array section 30.The driving section includes a signal-line driving section 40, ascanning-line driving section 50 and a driving-timing generation section60. Typically, the driving section is integrated on the same substrate,which serves as the liquid-crystal display panel 11 _(A), as the pixelarray section 30. Integrated in such a state, the driving section drivesthe pixels 20 included in the pixel array section 30.

In the liquid-crystal display apparatus 10 shown in FIG. 1, the pixels20 form a matrix consisting of m rows and n columns on the pixel arraysection 30. In the pixel matrix, signal lines 31 ₁ to 31 _(n) arestretched in the column direction. In the following description, each ofthe signal lines 31 ₁ to 31 _(n) is also referred to simply as a signalline 31 in some cases. The signal line 31 is provided for each pixelcolumn. In addition, in the pixel matrix, scanning lines 32 ₁ to 32 _(m)are stretched in the row direction. In the following description, eachof the scanning lines 32 ₁ to 32 _(m) is also referred to simply as ascanning line 32 in some cases. The scanning line 32 is provided foreach pixel row.

A specific end of each of the signal lines 31 ₁ to 31 _(n) is connectedto an output terminal of a column of the signal-line driving section 40.The signal-line driving section 40 operates to output a signal electricpotential reflecting a gradation to the signal line 31 supposed toreceive the electric potential.

A specific end of each of the scanning lines 32 ₁ to 32 _(m) isconnected to an output terminal of a row of the scanning-line drivingsection 50. The scanning-line driving section 50 controls operations towrite the signal electric potentials, which have been output by thesignal-line driving section 40 to the signal lines 31 ₁ to 31 _(n) assignal electric potentials each reflecting a gradation, into the pixels20.

The driving-timing generation section 60 also referred to as a TG(Timing Generator) provides the signal-line driving section 40 and thescanning-line driving section 50 with a variety of driving pulses alsoreferred to as timing signals for driving the signal-line drivingsection 40 and the scanning-line driving section 50.

2-2: Pixel Circuit

Next, by referring to FIG. 2, the following description explains thebasic circuit configuration of the pixels 20 composing the pixel arraysection 30.

As shown in FIG. 2, a plurality of signal lines 31 (that is, signallines 31 ₁ to 31 _(n)) are provided to intersect a plurality of scanninglines 32 (that is, scanning lines 32 ₁ to 31 _(m)) at intersections and,at each of the intersections, a pixel array section 30 is created.

The pixel 20 typically includes a pixel transistor 21, a liquid-crystalcapacitor 22 and an electric-charge holding capacitor 23. The pixeltransistor 21 is typically a TFT (Thin Film Transistor). The gateelectrode of the pixel transistor 21 is connected to a scanning line 32(that is, one of the scanning lines 32 ₁ to 32 _(m)). On the other hand,a specific one of the source and drain electrodes of the pixeltransistor 21 is connected to a signal line 31 (that is, one of thesignal lines 31 ₁ to 31 _(n)).

The liquid-crystal capacitor 22 implies a capacitive component of aliquid-crystal material generated between a pixel electrode and anopposite electrode created to face the pixel electrode. The pixelelectrode of the liquid-crystal capacitor 22 is connected to the otherone of the source and drain electrodes of the pixel transistor 21. A DCcommon voltage V_(com) common to all pixels 20 is applied to theopposite electrode of the liquid-crystal capacitor 22. A specificelectrode of the electric-charge holding capacitor 23 is connected tothe pixel electrode of the liquid-crystal capacitor 22 whereas the otherelectrode of the electric-charge holding capacitor 23 is connected tothe opposite electrode of the liquid-crystal capacitor 22.

By the way, in the case of a display apparatus for showing colordisplays, that is, in the case of a liquid-crystal display apparatustaken as an example of the display apparatus, each pixel 20 shown inFIGS. 1 and 2 serves as each of sub-pixels included in a pixel used as aunit in formation of a color image.

3: First Embodiment

The pixel array according to the first embodiment is a pixel array inwhich one pixel used as a unit in formation of a color image includesthree sub-pixels. In addition, each pixel in the pixel array accordingto the first embodiment can be a first pixel including three sub-pixelsfor displaying three primary colors respectively or a second pixelincluding three sub-pixels for displaying two colors selected among thethree primary colors and a predetermined color other than the threeprimary colors. The first and second pixels are laid out alternately inthe row and column directions.

The first pixel of the pixel array according to the first embodiment ischaracterized in that the size of the display surface of a sub-pixel fordisplaying a specific color included in the three primary colors as aspecific color missing from the second pixel is larger than each of thesizes of the display surfaces of the two other sub-pixels for displayingthe two other primary colors respectively.

The following description explains concrete typical implementations ofthe pixel array according to the first embodiment. In these typicalimplementations, the specific color included in the three primary colorsas a specific color missing from the second pixel is the B (blue) colorwhereas, in the second pixel, the predetermined color serving as asubstitute for the B (blue) color missing from the second pixel is the W(white) color.

3-1: First Typical Implementation

FIG. 3 is a diagram showing the top view of a pixel array according to afirst typical implementation of the first embodiment. In order tosimplify the figure, the figure shows only four adjacent pixels on theupper, lower, left and right sides respectively.

As shown in FIG. 3, the pixel array according to the first typicalimplementation includes two first pixels 20 ₁ and two second pixels 20₂. The two first pixels 20 ₁ each include three sub-pixels fordisplaying three primary colors respectively whereas the two secondpixels 20 ₂ each include three sub-pixels for displaying respectivelytwo colors selected among the three primary colors and a predeterminedcolor other than the three primary colors. The two first pixels 20 ₁ andthe two second pixels 20 ₂ are laid out alternately in the row andcolumn directions to form a pixel matrix.

To put it in detail, the first pixel 20 ₁ is configured to include threesub-pixels 20 _(R), 20 _(G) and 20 _(B) for displaying the three RGBprimary colors respectively. In this first pixel 20 ₁, the size of thedisplay surface of the R sub-pixel 20 _(R) is about ⅓ of the total sizeof the entire first pixel 20 ₁. On the other hand, the size of thedisplay surface of the G sub-pixel 20 _(G) is made smaller than the sizeof the display surface of the R sub-pixel 20 _(R). For example, the sizeof the display surface of the G sub-pixel 20 _(G) is set at about 80% ofthe size of the display surface of the R sub-pixel 20 _(R).

Then, the remaining area becoming available in the first pixel 20 ₁ isallocated to the B sub-pixel 20 _(B). Thus, in the first pixel 20 ₁, therelations between the sizes of the display surfaces of the R sub-pixel20 _(R), the G sub-pixel 20 _(G) and the B sub-pixel 20 _(B) can bedescribed as follows. The size of the display surface of the B sub-pixel20 _(B) is largest whereas the size of the display surface of the Gsub-pixel 20 _(G) is smallest. That is to say, the size of the displaysurface of the R sub-pixel 20 _(R) is between the size of the displaysurface of the B sub-pixel 20 _(B) and the size of the display surfaceof the G sub-pixel 20 _(G).

The second pixel 20 ₂ is configured to include three sub-pixels. Thethree sub-pixels include two sub-pixels 20 _(R) and 20 _(G) fordisplaying the R and G primary colors respectively in addition to asub-pixel 20 _(W) for displaying the predetermined color which is thewhite color. In this second pixel 20 ₂, the size of the display surfaceof the R sub-pixel 20 _(R) is about ⅓ of the total size of the entiresecond pixel 20 ₂. That is to say, the size of the display surface ofthe R sub-pixel 20 _(R) in the second pixel 20 ₂ is about equal to thesize of the display surface of the R sub-pixel 20 _(R) in the firstpixel 20 ₁. Thus, it is possible to provide a stripe array in which theR sub-pixels 20 _(R) are laid out to form a straight line in the columndirection.

In the second pixel 20 ₂, the size of the display surface of the Gsub-pixel 20 _(G) is made smaller than the size of the display surfaceof the R sub-pixel 20 _(R). For example, the size of the display surfaceof the G sub-pixel 20 _(G) is set at about 80% of the size of thedisplay surface of the R sub-pixel 20 _(R). That is to say, the size ofthe display surface of the G sub-pixel 20 _(G) in the second pixel 20 ₂is about equal to the size of the display surface of the G sub-pixel 20_(G) in the first pixel 20 ₁. Thus, it is possible to provide a stripearray in which the G sub-pixels 20 _(G) are laid out to form a straightline in the column direction.

Then, the remaining area becoming available in the second pixel 20 ₂ isallocated to the W sub-pixel 20 _(W).

The size of the display surface of the W sub-pixel 20 _(W) is aboutequal to the size of the display surface of the B sub-pixel 20 _(B).Thus, it is possible to provide a stripe array in which the B sub-pixels20 _(B) and the W sub-pixels 20 _(W) are laid out alternately to form astraight line in the column direction.

By the same token, in the second pixel 20 ₂, the relations between thesizes of the display surfaces of the R sub-pixel 20 _(R), the Gsub-pixel 20 _(G) and the W sub-pixel 20 _(W) can be described asfollows. The size of the display surface of the W sub-pixel 20 _(W) islargest whereas the size of the display surface of the G sub-pixel 20_(G) is smallest. That is to say, the size of the display surface of theR sub-pixel 20 _(R) is between the size of the display surface of the Wsub-pixel 20 _(W) and the size of the display surface of the G sub-pixel20 _(G).

As described above, the pixel array according to the first typicalimplementation is configured to include the first pixel 20 ₁ includingthree sub-pixels 20 _(R), 20 _(G) and 20 _(B) for displaying the threeRGB primary colors respectively as well as the second pixel 20 ₂including two sub-pixels 20 _(R) and 20 _(G) for displaying the R and Gprimary colors respectively and a sub-pixel 20 _(W) for displaying thewhite color. In addition, the pixel array according to the first typicalimplementation is configured into a configuration in which, in a processof adding the W sub-pixel 20 _(W) to the second pixel 20 ₂ to serve as asubstitute for the B sub-pixel 20 _(B) missing from the second pixel 20₂, the size (or the area) of the display surface of the G sub-pixel 20_(G) is reduced in order to enlarge the size of the display surface ofthe B sub-pixel 20 _(B) by an increase determined by the reduction ofthe size of the display surface of the G sub-pixel 20 _(G).

By adopting such a configuration, the effective color component of the Bcolor missing from the second pixel 20 ₂ is increased. Thus, it ispossible to decrease a shift caused by the disappearance of the B colorfrom the second pixel 20 ₂ as the shift of the chromaticity of the whitecolor to the side of the supplementary-color system. In addition,without means adopted in a light blocking film referred to as a blackmatrix or in a light blocking metal on a TFT array side to serve asmeans for blocking light propagating through desired sub-pixels, it ispossible to decrease the shift of the chromaticity of the white color tothe side of the supplementary-color system. Thus, it is possible toimprove performance deteriorations caused by the yellow-color transitionof the chromaticity of the white color while sustaining thetransmittance of the display panel.

In this case, as shown in FIG. 4, designs 1 to 5 are conceivable. Inthese designs, the size of the display surface of the G sub-pixel 20_(G) is changed by a multiplying factor in a range of 1.0 to 0.8 whereasthe sizes of the display surfaces of the B sub-pixel 20 _(B) and the Wsub-pixel 20 _(W) are changed by a multiplying factor in a range of 1.0to 1.2. With such designs, the chromaticity of the white color is shownin FIG. 5 whereas the transmittance of the display panel is shown inFIG. 6. It is to be noted that the multiplying factor of 1 is used forthe size of a display surface for a case in which the pixel is dividedequally into three sub-pixels. That is to say, the multiplying factor of1 corresponds to a display-surface size equal to ⅓ of the size of thepixel.

First of all, changes to settings 1 to 5 corresponding to designs 1 to 5respectively are examined to check an effect on the chromaticity of thewhite color. If the size of the display surface of the G sub-pixel 20_(G) is reduced whereas the size of the display surface of the Bsub-pixel 20 _(B) is increased as shown in FIG. 4, performancedeteriorations caused by the yellow-color transition of the chromaticityof the white color are improved. That is to say, as is obvious from FIG.5, the chromaticity of the white color gradually changes to match atarget chromaticity.

Next, changes to settings 1 to 5 are examined to check an effect on thetransmittance of the display panel. If the size of the display surfaceof the G sub-pixel 20 _(G) is reduced, the transmittance of the Gsub-pixel 20 _(G) decreases. However, the size of the display surface ofthe W sub-pixel 20 _(W) is increased at the same time. Thus, thetransmittance of the W sub-pixel 20 _(W) increases so that it is obviousthat the transmittance of the display panel does not change as shown inFIG. 6. That is to say, with the changes to settings 1 to 5, it ispossible to improve performance deteriorations caused by theyellow-color transition of the chromaticity of the white color whilesustaining the transmittance of the display panel.

3-2: Second Typical Implementation

FIG. 7 is a diagram showing the top view of a pixel array according to asecond typical implementation of the first embodiment. Also in thiscase, in order to simplify the figure, the figure shows only fouradjacent pixels on the upper, lower, left and right sides respectively.

As shown in FIG. 7, in the same way as the pixel array according to thefirst typical implementation, the pixel array according to the secondtypical implementation also includes two first pixels 20 ₂ and twosecond pixels 20 ₂. The two first pixels 20 ₁ each include threesub-pixels for displaying three primary colors respectively whereas thetwo second pixels 20 ₂ each include three sub-pixels for displayingrespectively two colors selected among the three primary colors and apredetermined color other than the three primary colors. The two firstpixels 20 ₁ and the two second pixels 20 ₂ are laid out alternately inthe row and column directions to form a pixel matrix.

To put it in detail, the first pixel 20 ₂ is configured to include threesub-pixels 20 _(R), 20 _(G) and 20 _(B) for displaying the three RGBprimary colors respectively. In this first pixel 20 ₁, the sizes of thedisplay surfaces of the R sub-pixel 20 _(R) and the G sub-pixel 20 _(G)are each made smaller than ⅓ of the total size of the entire first pixel20 ₁. For example, the sizes of the display surfaces of the R sub-pixel20 _(R) and the G sub-pixel 20 _(G) are each set at about 80% of ⅓ ofthe total size of the entire first pixel 20 ₁. Then, the remaining areabecoming available in the first pixel 20 ₁ is allocated to the Bsub-pixel 20 _(B).

Thus, in the first pixel 20 ₁, a relation between the sizes of thedisplay surfaces of the three sub-pixels (that is, the R sub-pixel 20 ₂,the G sub-pixel 20 _(G) and the B sub-pixel 20 _(B)) can be described asfollows. The size of the display surface of the B sub-pixel 20 _(B) isvery large in comparison with each of the sizes of the display surfacesof the R sub-pixel 20 _(B) and the G sub-pixel 20 _(G).

The second pixel 20 ₂ is configured to include three sub-pixels. Thethree sub-pixels include two sub-pixels 20 ₂ and 20 _(G) for displayingthe R and G primary colors respectively in addition to a sub-pixel 20_(W) for displaying the predetermined color which is the white color. Inthis second pixel 20 ₂, the sizes of the display surfaces of the Rsub-pixel 20 ₂ and the G sub-pixel 20 _(G) are each made smaller than ⅓of the total size of the entire second pixel 20 ₂. For example, thesizes of the display surfaces of the R sub-pixel 20 _(R) and the Gsub-pixel 20 _(G) are each set at about 80% of ⅓ of the total size ofthe entire second pixel 20 ₂. Then, the remaining area becomingavailable in the second pixel 20 ₂ is allocated to the W sub-pixel 20_(W).

Thus, in the second pixel 20 ₂, a relation between the sizes of thedisplay surfaces of the three sub-pixels (that is, the R sub-pixel 20_(R), the G sub-pixel 20 ₂ and the W sub-pixel 20 _(W)) can be describedas follows. The size of the display surface of the W sub-pixel 20 _(W)is very large in comparison with each of the sizes of the displaysurfaces of the R sub-pixel 20 _(R) and the G sub-pixel 20 _(G).

In addition, in the first pixel 20 ₁ and the second pixel 20 ₂, it ispossible to provide a stripe array in which the R sub-pixels 20 _(B) arelaid out to form a straight line in the column direction whereas the Gsub-pixels 20 _(G) are also laid out to form a straight line in thecolumn direction. On top of that, in the first pixel 20 ₁ and the secondpixel 20 ₂, it is possible to provide a stripe array in which the Bsub-pixels 20 _(B) and the W sub-pixels 20 _(W) are laid out alternatelyto form a straight line in the column direction.

As described above, the pixel array according to the second typicalimplementation is configured into a configuration in which, in a processof adding the W sub-pixel 20 _(W) to the second pixel 20 ₂ to serve as asubstitute for the B sub-pixel 20 _(B) missing from the second pixel 20₂, the sizes of the display surfaces of the R sub-pixel 20 _(R) and theG sub-pixel 20 _(G) are reduced in order to enlarge each of the sizes ofthe display surfaces of the B sub-pixel 20 _(B) and the W sub-pixel 20_(W) by an increase determined by the reduction of the sizes of thedisplay surfaces of the R sub-pixel 20 _(R) and the G sub-pixel 20 _(G).

By adoption of the configuration described above, it is possible toobtain the same effects as the pixel array according to the firsttypical implementation. In addition, since the sizes of the displaysurfaces of the R sub-pixel 20 _(R) and the G sub-pixel 20 _(G) areadjusted, there is provided a merit that the freedom to adjust thechromaticity of the white color can be raised to a level higher thanthat of the pixel array according to the first typical implementation.That is to say, the range for adjusting the chromaticity of the whitecolor can be broadened to a range wider than that of the pixel arrayaccording to the first typical implementation.

3-3: Third Typical Implementation

FIG. 8 is a diagram showing the top view of a pixel array according to athird typical implementation of the first embodiment. Also in this case,in order to simplify the figure, the figure shows only four adjacentpixels on the upper, lower, left and right sides respectively.

As shown in FIG. 8, in the same way as the pixel arrays according to thefirst and second typical implementations, the pixel array according tothe third typical implementation also includes two first pixels 20 ₂ andtwo second pixels 20 ₂. The two first pixels 20 ₂ each include threesub-pixels for displaying three primary colors respectively whereas thetwo second pixels 20 ₂ each include three sub-pixels for displayingrespectively two colors selected among the three primary colors and apredetermined color other than the three primary colors. The two firstpixels 20 ₂ and the two second pixels 20 ₂ are laid out alternately inthe row and column directions to form a pixel matrix.

To put it in detail, the first pixel 20 ₂ is configured to include threesub-pixels 20 _(R), 20 _(G) and 20 _(B) for displaying the three RGBprimary colors respectively. In this first pixel 20 ₁, the size of thedisplay surface of the G sub-pixel 20 _(G) is made about equal to ⅓ ofthe total size of the entire first pixel 20 ₁. In addition, the size ofthe display surface of the R sub-pixel 20 _(R) is made smaller than thesize of the display surface of the G sub-pixel 20 _(G). For example, thesize of the display surface of the R sub-pixel 20 _(R) is set at about80% of the size of the display surface of the G sub-pixel 20 _(G).

Then, the remaining area becoming available in the first pixel 20 ₁ isallocated to the B sub-pixel 20B. Thus, in the first pixel 20 ₁, arelation between the sizes of the display surfaces of the threesub-pixels (that is, the R sub-pixel 20 _(R), the G sub-pixel 20 _(G)and the B sub-pixel 20 _(B)) can be described as follows. The size ofthe display surface of the B sub-pixel 20 _(B) is largest whereas thesize of the display surface of the R sub-pixel 20 _(R) is smallest. Thatis to say, the size of the display surface of the G sub-pixel 20 _(G) isbetween the size of the display surface of the B sub-pixel 20 _(B) andthe size of the display surface of the R sub-pixel 20 _(R).

The second pixel 20 ₂ is configured to include three sub-pixels. Thethree sub-pixels include two sub-pixels 20 _(R) and 20 _(G) fordisplaying the R and G primary colors respectively in addition to asub-pixel 20 _(W) for displaying the predetermined color which is thewhite color. In this second pixel 20 ₂, the size of the display surfaceof the G sub-pixel 20 _(G) is about ⅓ of the total size of the entiresecond pixel 20 ₂. That is to say, the size of the display surface ofthe G sub-pixel 20 _(G) in the second pixel 20 ₂ is about equal to thesize of the display surface of the G sub-pixel 20 _(G) in the firstpixel 20 ₁. Thus, it is possible to provide a stripe array in which theG sub-pixels 20 _(G) are laid out to form a straight line in the columndirection.

In addition, in the second pixel 20 ₂, the size of the display surfaceof the R sub-pixel 20 _(R) is made smaller than the size of the displaysurface of the G sub-pixel 20 _(G). For example, the size of the displaysurface of the R sub-pixel 20 _(R) is set at about 80% of the size ofthe display surface of the G sub-pixel 20 _(G). That is to say, the sizeof the display surface of the R sub-pixel 20 _(R) in the second pixel 20₂ is about equal to the size of the display surface of the R sub-pixel20 _(R) in the first pixel 20 ₁. Thus, it is possible to provide astripe array in which the R sub-pixels 20 _(R) are laid out to form astraight line in the column direction. Then, the remaining area becomingavailable in the second pixel 20 ₂ is allocated to the W sub-pixel 20_(W).

The size of the display surface of the W sub-pixel 20 _(W) is aboutequal to the size of the display surface of the B sub-pixel 20 ₂. Thus,it is possible to provide a stripe array in which the B sub-pixels 20_(R) and the W sub-pixels 20 _(W) are laid out alternately to form astraight line in the column direction. In addition, in the second pixel20 ₂, a relation between the sizes of the display surfaces of the threesub-pixels (that is, the R sub-pixel 20 _(R), the G sub-pixel 20 _(G)and the W sub-pixel 20 _(W)) can be described as follows. The size ofthe display surface of the W sub-pixel 20 _(W) is largest whereas thesize of the display surface of the R sub-pixel 20 _(R) is smallest. Thatis to say, the size of the display surface of the G sub-pixel 20 _(G) isbetween the size of the display surface of the W sub-pixel 20 _(W) andthe size of the display surface of the R sub-pixel 20 _(R).

As described above, the pixel array according to the third typicalimplementation is configured into a configuration in which, in a processof adding the W sub-pixel 20 _(W) to the second pixel 20 ₂ to serve as asubstitute for the B sub-pixel 20 _(B) missing from the second pixel 20₂, the size of the display surface of the R sub-pixel 20 _(R) is reducedin order to enlarge the size of the display surface of the B sub-pixel20 _(B) by an increase determined by the reduction of the size of thedisplay surface of the R sub-pixel 20 _(R). Nevertheless, it is possibleto obtain the same effects as the pixel array according to the firsttypical implementation.

4: Second Embodiment

The pixel array according to a second embodiment of the presentdisclosure is a pixel array in which each pixel used as a unit information of a color image includes four sub-pixels. The four sub-pixelsinclude three sub-pixels for displaying the three primary colorsrespectively and one sub-pixel for displaying a predetermined colorother than the three primary colors. The pixels are laid out repeatedlyin the row and column directions.

In addition, the pixel array according to the second embodiment ischaracterized in that the size of a sub-pixel for displaying a specificcolor selected from the three primary colors is made smaller than eachof the sizes of the sub-pixels for displaying the two other primarycolors but larger than half the size of each of the sub-pixels fordisplaying the two other primary colors. A concrete typicalimplementation of the second embodiment is explained below. In thetypical implementation, the specific color selected from the threeprimary colors is the B (blue) color whereas the predetermined color isthe W (white) color.

4-1: Typical Implementation

FIG. 9 is a diagram showing the top view of a pixel array according to atypical implementation of the second embodiment. Also in this case, inorder to simplify the figure, the figure shows only four adjacent pixelson the upper, lower, left and right sides respectively.

As shown in FIG. 9, in the pixel array according to the typicalimplementation of the second embodiment of the present disclosure, eachpixel 20 _(A) used as a unit in formation of a color image includes foursub-pixels. The four sub-pixels include three sub-pixels 20 _(R), 20_(G) and 20 _(B) for displaying the three primary colors respectivelyand one sub-pixel 20 _(W) for displaying a predetermined color otherthan the three primary colors. The pixels are laid out repeatedly in therow and column directions.

In the configuration described above, each of the sizes of the Rsub-pixel 20 _(R) and the G sub-pixel 20 _(G) is set at a value smallerthan ⅓ of the size of the pixel 20 _(A). In addition, in the case ofthis typical implementation, the size of the R sub-pixel 20 _(R) is madeequal to the size of the G sub-pixel 20 _(G). An available area is anarea remaining in the pixel 20 _(A) as a result of subtracting areasallocated to the R sub-pixel 20 _(R) and the G sub-pixel 20 _(G) fromthe area of the pixel 20 _(A). Thus, the size of the available area islarger than ⅓ of the size of the pixel 20 _(A). It is to be noted thatthe size of the R sub-pixel 20 _(R) does not have to be equal to thesize of the G sub-pixel 20 _(G).

Then, the available area remaining in the pixel 20 _(A) as a result ofsubtracting areas allocated to the R sub-pixel 20 _(R) and the Gsub-pixel 20 _(G) from the area of the pixel 20 _(A) is allocated to theB sub-pixel 20 _(B) and the W sub-pixel 20 _(W). In addition, in thecase of this typical implementation, the size of the B sub-pixel 20 _(B)is made equal to the size of the W sub-pixel 20 _(W). Thus, each of thesizes of the W sub-pixel 20 _(W) and the B sub-pixel 20 _(B) is smallerthan each of the sizes of the R sub-pixel 20 _(R) and the G sub-pixel 20_(G) but larger than half the size of each of the R sub-pixel 20 _(R)and the G sub-pixel 20 _(G). It is to be noted that the size of the Bsub-pixel 20 _(B) does not have to be equal to the size of the Wsub-pixel 20 _(W).

As described above, the size of the B sub-pixel 20 _(B) for displayingthe blue color which is the specific color selected from the threeprimary colors is made smaller than each of the sizes of the R sub-pixel20 _(R) and the G sub-pixel 20 _(G) for displaying the two other primarycolors respectively. Since the size of the B sub-pixel 20 _(B) isdecreased, an available area resulting from the reduction of the size ofthe B sub-pixel 20 _(B) can be allocated to the W sub-pixel 20 _(W). Inthis way, each pixel 20 _(A) includes a W sub-pixel 20 _(W) increasingthe luminance. In addition, each pixel 20 _(A) also includes the Rsub-pixel 20 _(G), the G sub-pixel 20 _(G) and the B sub-pixel 20 _(B)for displaying all the primary colors. Thus, the resolution is alsoimproved as well.

By the way, if the size of the B sub-pixel 20 _(E) is made equal to halfthe size of each of the R sub-pixel 20 _(R) and the G sub-pixel 20 _(G),the component of the blue color also becomes half the quantity of eachof the color components of the red and green colors. That is to say,this configuration provides the same optical characteristic as a pixelarray shown in FIG. 10 as the pixel array according to the existingtechnology. This optical characteristic raises the problem of theyellow-color transition for the chromaticity of the white color due tothe same reason explained earlier in the description of the pixel arrayaccording to the existing technology.

On the other hand, the pixel array according to this typicalimplementation has a configuration in which the size of the B sub-pixel20 _(B) is made larger than half the size of each of the R sub-pixel 20_(R) and the G sub-pixel 20 _(G). Thus, in comparison with aconfiguration in which the size of the B sub-pixel 20 _(B) is made equalto half the size of each of the R sub-pixel 20 _(R) and the G sub-pixel20 _(G), the component of the blue color also becomes large. As aresult, it is possible to decrease a shift caused by the yellow-colortransition as a shift of the chromaticity of the white color. Inaddition, without means adopted in a light blocking film referred to asa black matrix or in a light blocking metal on a TFT array side to serveas means for blocking light propagating through desired sub-pixels, itis possible to decrease a shift caused by the yellow-color transition asa shift of the chromaticity of the white color. Thus, it is possible toimprove performance deteriorations caused by the yellow-color transitionof the chromaticity of the white color while sustaining thetransmittance of the display panel.

5: Liquid-Crystal Display Apparatus of a Horizontal Electric-Field Mode

The above descriptions explain a liquid-crystal display apparatusserving as a display apparatus for showing color displays. The operatingmode of the liquid-crystal display apparatus is not prescribed inparticular. In the case of a horizontal electric-field mode, however, itis desirable to adopt countermeasures described as follows.

In the case of a horizontal electric-field mode, the pattern of thetransparent pixel electrode has a comb-tooth shape. In addition, if thesize of a sub-pixel is changed, the aperture ratio is adjusted bychanging a comb-tooth count which is the number of comb teeth. If thenumber of comb teeth is changed, however, the area of the pixelelectrode varies from sub-pixel to sub-pixel. Thus, the pixelcapacitance also varies as well. In some cases, the variations of thepixel capacitance raise a problem of worsening flickers and a problem ofdeteriorating printing.

Thus, it is desirable to conduct a design in which the area of the pixelelectrode is typically adjusted for insertion as much as possible bymaking use of an area not contributing to the transmittance of thedisplay panel. A typical example of the area not contributing to thetransmittance of the display panel is a light blocking area having nooptical effects. To put it concretely, the areas of pixel electrodes aremade uniform by, for example, increasing the areas of the pixelelectrodes for sub-pixels each having a reduced comb-tooth count. Inthis case, the technical term ‘uniform’ implies not only ‘strictlyuniform,’ but also ‘substantially uniform.’ Existence of a variety ofvariations generated at the design stage or the manufacturing stage istolerated.

In addition, if the problem of worsening flickers and the problem ofdeteriorating printing are caused by a shift of the DC common voltageV_(com) applied to sub-pixels as shown in FIG. 2 from an optimum level,it is desirable to adopt a countermeasure described below. It is to benoted that the shift of the DC common voltage V_(com) is caused byvariations of the pixel capacitances of the individual sub-pixels.

If the problems are caused by such a shift, the driver IC of theliquid-crystal display apparatus is provided with a function forindependently controlling the center values of signal levels of thesub-pixels by typically giving offsets independently to the centervalues. With such a function, the shift of the DC common voltage V_(com)can be cancelled so that it is possible to solve the problem ofworsening flickers and the problem of deteriorating printing. Asdescribed above, the shift of the DC common voltage V, is caused byvariations of the pixel capacitances of the sub-pixels.

6: Electronic Equipment

The display apparatus provided by the embodiments of the presentdisclosure as described above can be applied to electronic equipment inall fields. In this case, the display apparatus functions as a displaysection employed in the electronic equipment. The display section is asection for displaying a video signal supplied to the electronicequipment or a video signal generated in the electronic equipment. Thevideo signal is displayed as an image or a video picture.

As is obvious from the earlier descriptions of the embodiments, thedisplay apparatus according to the embodiments of the present disclosureis characterized in that the display apparatus is capable of reducingthe shift of the chromaticity of the white color to the side of thesupplementary-color system while enhancing the display performance suchas the luminance so that more excellent color displays can beimplemented. Thus, by applying the display apparatus according to theembodiments of the present disclosure to electronic equipment in allfields as the display section of the equipment, the equipment can bemade capable of implementing more excellent color displays.

Typical examples of the electronic equipment employing the displayapparatus according to the embodiments of the present disclosure as thedisplay section of the equipment are a digital camera, a video camera, aPDA (Personal Digital Assistant), a game machine, a notebook personalcomputer, a mobile information terminal such as an electronic book and amobile communication terminal such as a cellular phone.

7: Configurations of the Disclosure

It is to be noted that the present disclosure can also be realized intothe following implementations.

1. A display apparatus including:

a first pixel including three sub-pixels for displaying three primarycolors respectively; and

a second pixel including three sub-pixels for displaying two colorsselected among the three primary colors and a predetermined color otherthan the three primary colors,

wherein, in the first pixel, the size of the display surface of asub-pixel for displaying a specific color included in the three primarycolors as a specific color missing from the second pixel is larger thaneach of the sizes of the display surfaces of the two other sub-pixelsfor displaying the two other primary colors respectively.

2. The display apparatus according to implementation 1 wherein, in thesecond pixel, the size of the display surface of the sub-pixel fordisplaying the predetermined color is larger than each of the sizes ofthe display surfaces of the two other sub-pixels for displayingrespectively the two primary colors selected among the three primarycolors.

3. The display apparatus according to implementation 1 or 2 wherein thesize of the display surface of a sub-pixel included in the first pixelto serve as the sub-pixel for displaying the specific color selectedamong the three primary colors is equal to the size of the displaysurface of a sub-pixel included in the second pixel to serve as thesub-pixel for displaying the predetermined color.

4. The display apparatus according to any one of implementations 1 to 3wherein the first pixels and the second pixels are laid out alternatelyin a direction parallel to pixel rows and a direction parallel to columnrows.

5. The display apparatus according to any one of implementations 1 to 4wherein the predetermined color is a white color.

6. The display apparatus according to any one of implementations 1 to 5wherein the specific color selected among the three primary colors as acolor missing from the second pixel is a blue color.

7. The display apparatus according to implementation 6 wherein:

in the first pixel, the size of the display surface of the sub-pixel fordisplaying the blue color is larger than the size of the display surfaceof the sub-pixel for displaying a green color; and

in the second pixel, the size of the display surface of the sub-pixelfor displaying the white color is larger than the size of the displaysurface of the sub-pixel for displaying the green color.

8. The display apparatus according to implementation 7 wherein, in thefirst and second pixels, the size of the display surface of thesub-pixel for displaying a red color is larger than the size of thedisplay surface of the sub-pixel for displaying the green color.

9. The display apparatus according to implementation 7 wherein, in thefirst and second pixels, the size of the display surface of thesub-pixel for displaying a red color is equal to the size of the displaysurface of the sub-pixel for displaying the green color.

10. The display apparatus according to implementation 9 wherein:

in the first pixel, the size of the display surface of the sub-pixel fordisplaying the blue color is larger than the sum of the size of thedisplay surface of the sub-pixel for displaying the red color and thesize of the display surface of the sub-pixel for displaying the greencolor; and

in the second pixel, the size of the display surface of the sub-pixelfor displaying the white color is larger than the sum of the size of thedisplay surface of the sub-pixel for displaying the red color and thesize of the display surface of the sub-pixel for displaying the greencolor.

11. The display apparatus according to implementation 7 wherein, in thefirst and second pixels, the size of the display surface of thesub-pixel for displaying the green color is larger than the size of thedisplay surface of the sub-pixel for displaying a red color.

12. A display apparatus having pixels each including four sub-pixels fordisplaying respectively three primary colors and a predetermined colorother than the three primary colors wherein the size of the sub-pixelfor displaying a specific color selected from the three primary colorsis smaller than each of the sizes of the sub-pixels for displaying thetwo other primary colors but larger than half the size of each of thesub-pixels for displaying the two other primary colors.

13. The display apparatus according to implementation 12 wherein thesize of the sub-pixel for displaying the specific color selected fromthe three primary colors is equal to the size of the sub-pixel fordisplaying the predetermined color.

14. The display apparatus according to implementation 12 or 13 whereinthe pixels are laid out repeatedly in a direction parallel to pixel rowsand a direction parallel to column rows.

15. The display apparatus according to any one of implementations 12 to14 wherein the predetermined color is a white color.

16. The display apparatus according to any one of implementations 12 to15 wherein the specific color selected among the three primary colors isa blue color.

17. The display apparatus according to implementation 16 wherein thesize of the sub-pixel for displaying the blue color is equal to the sizeof the sub-pixel for displaying the predetermined color.

18. The display apparatus according to implementation 16 wherein thesize of the sub-pixel for displaying a red color is equal to the size ofthe sub-pixel for displaying a green color.

19. Electronic equipment including a display apparatus including:

a first pixel including three sub-pixels for displaying three primarycolors respectively; and

a second pixel including three sub-pixels for displaying two colorsselected among the three primary colors and a predetermined color otherthan the three primary colors,

wherein, in the first pixel, the size of the display surface of asub-pixel for displaying a specific color included in the three primarycolors as a specific color missing from the second pixel is larger thaneach of the sizes of the display surfaces of the two other sub-pixelsfor displaying the two other primary colors respectively.

20. Electronic equipment employing a display apparatus having pixelseach including four sub-pixels for displaying respectively three primarycolors and a predetermined color other than the three primary colorswherein each of the size of the sub-pixel for displaying a specificcolor selected from the three primary colors and the size of thesub-pixel for displaying the predetermined color is smaller than each ofthe sizes of the sub-pixels for displaying the two other primary colors.

The present disclosure contains subject matter related to that disclosedin Japanese Priority Patent Application JP 2011-257336 filed in theJapan Patent Office on Nov. 25, 2011, the entire content of which ishereby incorporated by reference.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors in so far as they arewithin the scope of the appended claims or the equivalents thereof.

What is claimed is:
 1. A display apparatus comprising: a first pixelincluding three sub-pixels for respectively displaying red, green andblue; and a second pixel including three sub-pixels for respectivelydisplaying red, green and white, wherein, in said first pixel, a size ofa display surface of the sub-pixel for displaying blue, blue being asub-pixel displaying color absent from said second pixel, is larger thaneach of the sizes of display surfaces of the two other sub-pixels of thefirst pixel that are for respectively displaying red and green; and insaid second pixel, a size of a display surface of said sub-pixel fordisplaying white is larger than each of the sizes of display surfaces ofthe two other sub-pixels of the second pixel that are forrespectively-displaying red and green, a green size is a size of adisplay surface of said sub-pixel for displaying green, a red size is asize of a display surface of said sub-pixel for displaying red, a bluesize is a size of the display surface of said sub-pixel for displayingblue, a white size is a size of the display surface of said sub-pixelfor displaying white, at a manufacturing stage, the green size in thefirst pixel is set to be decreased from 95% to 80% of the red size asthe blue size is set to be increased from 105% to 120% of the red size,and at a manufacturing stage, the green size in the second pixel is setto be decreased from 95% to 80% of the red size as the white size is setto be increased from 105% to 120% of the red size.
 2. The displayapparatus according to claim 1, wherein the blue size in said firstpixel is equal to the white size in said second pixel.
 3. The displayapparatus according to claim 1, wherein said first pixel and said secondpixel are laid out alternately in a direction parallel to pixel rows anda direction parallel to pixel columns.
 4. The display apparatusaccording to claim 1, wherein the green size is substantially 80% of thered size, the blue size and the white size is substantially 120% of thered size.
 5. The display apparatus according to claim 1, wherein a basicsize is a third of a size of a display surface of each of said first andsecond pixels, and the red size is the basic size.
 6. An electronicdevice including a display apparatus comprising: a first pixel includingthree sub-pixels for respectively displaying red, green and blue; and asecond pixel including three sub-pixels for respectively displaying red,green and white, wherein, in said first pixel, a size of a displaysurface of the sub-pixel for displaying blue, blue being a sub-pixeldisplaying color absent from said second pixel, is larger than each ofthe sizes of display surfaces of the two other sub-pixels of the firstpixel that are for respectively displaying red and green; and in saidsecond pixel, a size of a display surface of said sub-pixel fordisplaying white is larger than each of the sizes of display surfaces ofthe two other sub-pixels of the second pixel that are forrespectively-displaying red and green, a green size is a size of adisplay surface of said sub-pixel for displaying green, a red size is asize of a display surface of said sub-pixel for displaying red, a bluesize is a size of the display surface of said sub-pixel for displayingblue, a white size is a size of the display surface of said sub-pixelfor displaying white, at a manufacturing stage, the green size in thefirst pixel is set to be decreased from 95% to 80% of the red size asthe blue size is set to be increased from 105% to 120% of the red size,and at a manufacturing stage, the green size in the second pixel is setto be decreased from 95% to 80% of the red size as the white size is setto be increased from 105% to 120% of the red size.